Polymerization process

ABSTRACT

Novel catalyst compositions, useful in the production of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon, comprise a compound of palladium, a Lewis acid of the formula MF n  wherein n is 3 or 5 and M is a Group III or V element which forms a binary fluoride, and a bidentate ligand of phosphorus, nitrogen or sulfur.

This is a continuation of application Ser. No. 833,201, filed Feb. 10,1992, and now U.S. Pat. No. 5,245,123.

FIELD OF THE INVENTION

This invention relates to a gas-phase process for the production oflinear alternating polymers of carbon monoxide and at least oneolefinically unsaturated hydrocarbon. The invention also relates tonovel catalyst compositions employed in that process.

BACKGROUND OF THE INVENTION

The class of linear alternating polymers of carbon monoxide and at leastone ethylenically unsaturated hydrocarbon is now well known in the art.These polymers, conventionally termed polyketones or polyketonepolymers, are of the general repeating formula ##STR1## wherein A is amoiety derived from at least one ethylenically unsaturated hydrocarbon.The scope of the process of producing the polyketone polymers isextensive, but typically employs a catalyst composition formed from acompound of palladium, the anion of a strong non-hydrohalogenic acid anda bidentate ligand of phosphorus, nitrogen or sulfur. Van Broekhoven etal, U.S. Pat. No. 4,843,144 and U.S. Pat. No. 4,880,903, illustrate theuse of bidentate ligands of phosphorus. Bidentate ligands of nitrogenare disclosed by U.S. Pat. No. 4,851,582 and bidentate ligands of sulfurare shown by U.S. Pat. No. 4,965,341.

It is also known that other acidic materials can be used instead of theanion of the strong non-hydrohalogenic acid. In U.S. Pat. No. 4,740,625and U.S. Pat. No. 4,851,582 there are disclosed catalyst compositionsproduced from a palladium salt, a bidentate ligand of phosphorus ornitrogen, and a Lewis acid which is a halide of germanium or tin. Thislatter process, conducted in slurry (liquid) phase in the presence ofliquid diluent, does not demonstrate a catalytic activity comparable tothe use of catalyst compositions formed from, inter alia, the anion ofstrong non-hydrohalogenic acid.

It is also known that the polymerization can be conducted in a gaseousphase in the substantial absence of liquid reaction diluent, e.g., as inU.S. Pat. No. 4,778,876. The use of a gas phase process offerssubstantial advantages in the separation and recovery of the polymerproduct which does not require separation from the liquid diluent of aslurry- or liquid-phase process. It would be of advantage to provideadditional gas-phase processes for the production of linear alternatingpolymers of carbon monoxide and at least one ethylenically unsaturatedhydrocarbon, as well as catalyst compositions useful in that process.

SUMMARY OF THE INVENTION

The present invention provides a gas-phase process for the production oflinear alternating polymers of carbon monoxide and at least oneethylenically unsaturated hydrocarbon. More particularly, the inventionprovides such a process conducted in the presence of a novel gas-phasecatalyst composition formed form a palladium compound, a Lewis acidcomprising a metal fluoride of defined structure and a bidentate ligandof phosphorus, nitrogen or sulfur.

DESCRIPTION OF THE INVENTION

The olefinically unsaturated hydrocarbons useful as precursors of thelinear alternating polymers have up to 20 carbon atoms inclusive,preferably up to 10 carbon atoms inclusive. These unsaturatedhydrocarbons are illustrated by aliphatic hydrocarbons includingethylene and other α-olefins such as propylene, 1-butene, isobutylene,1-hexene, 1-octene and 1-dodecene, as well as by arylaliphatichydrocarbons containing an aryl substituent on an otherwise aliphaticmolecule, particularly an aryl substituent on a carbon atom of theethylenic unsaturation. Illustrative of this latter class ofethylenically unsaturated hydrocarbons are styrene, p-methylstyrene,p-ethylstyrene and m-isopropylstyrene. Preferred linear alternatingpolymers are copolymers of carbon monoxide and ethylene or terpolymersof carbon monoxide, ethylene and a second ethylenically unsaturatedhydrocarbon of at least three carbon atoms, particularly an α-olefinsuch as propylene.

Within the preferred terpolymers of the invention there will be at leastabout two units incorporating moieties derived from ethylene for eachunit incorporating a moiety derived from the second ethylenicallyunsaturated hydrocarbon. Preferably, there will be from about 10 toabout 100 units incorporating moieties derived from ethylene for eachunit incorporating a moiety derived from the second ethylenicallyunsaturated hydrocarbon. The preferred polyketone polymers are thereforerepresented by the repeating formula ##STR2## wherein G is a moietyderived from the second ethylenically unsaturated hydrocarbon of atleast 3 carbon atoms polymerized through the ethylenic unsaturationthereof and the ratio of y:x is less than about 0.5. When the preferredcopolymers of carbon monoxide and ethylene are produced by the processof the invention, there will be no second hydrocarbon present and thecopolymers are represented by the above formula II wherein y is zero.When y is other than zero, i.e., terpolymers are produced, the--CO--(--CH₂ --CH₂ --) units and the --CO--(--G--)-- units are foundrandomly throughout the polymer chain and the preferred ratios of y:xare from about 0.01 to about 0.1. The end groups or "caps" of thepolymer chain will depend upon what materials were present duringpolymerization and whether and how the polymer was purified. The endgroups do not, however, contribute to the properties of the polymer toany substantial extent so that the polymers are fairly represented bythe formula for the polymeric chain as depicted above.

Of particular interest are the polyketone polymers of number averagemolecular weight from about 1,000 to about 200,000, especially thosepolymers of number average molecular weight from about 20,000 to about90,000, as determined by gel permeation chromatography. The propertiesof such polymers will depend in part upon the molecular weight, whetherthe polymer is a copolymer or a terpolymer and, in the case ofterpolymers, the nature of and the proportion of the second hydrocarbonpresent. Such polyketone polymers will typically have a melting pointfrom about 175° C. to about 300° C., but more often from about 210° C.to about 275° C. The polymers have a limiting viscosity number (LVN),measured in a standard capillary viscosity measuring device in m-cresolat 60° C., of from about 0.4 dl/g to about 10 dl/g, preferably fromabout 0.8 dl/g to about 4 dl/g.

The polymers are produced by contacting carbon monoxide andethylenically unsaturated hydrocarbon in the gaseous phase in thesubstantial absence of reaction diluent under polymerization conditionsin the presence of a catalyst composition formed from a compound ofpalladium, a Lewis acid of defined structure and a bidentate ligand ofphosphorous, nitrogen or sulfur. The compound of palladium is preferablya palladium carboxylate and palladium acetate, palladium propionate,palladium butyrate and palladium hexanoate are satisfactory. Palladiumacetate is particularly preferred.

The Lewis acid component of the catalyst composition is a fluoride ofthe formula MF_(n) wherein n is 3 or 5 and M is an element of Group IIIor V of the Periodic Table of Elements which forms a binary fluoride.Illustrative of "M" elements are boron, antimony, phosphorus, aluminum,gallium, arsenic, tantatum, niobium and indium. Suitable Lewis acids ofthe MF_(n) formula include boron trifluoride, antimony pentafluoride,phosphorus pentafluoride, aluminum trifluoride, gallium trifluoride,arsenic pentafluoride, tantatum pentafluoride and indium trifluoride.The use as a catalyst composition component of boron trifluoride oraluminum trifluoride is preferred. The Lewis acids are useful as such orare employed in the form of a complex with an oxygen-containingmolecule, e.g., the etherate or alcoholate. When complexes are used asthe source of the Lewis acid, a Lewis acid etherate is preferred,particularly a diethyl ether etherate although dibutyl ether etheratesare also useful. Especially preferred as the Lewis acid is borontrifluoride diethyl ether etherate. The Lewis acid is provided to thecatalyst composition in an amount about 0.5 mol to about 200 mols permol of palladium compound. Particularly preferred are quantities ofLewis acid from about 1 mol to about 100 mols per mol of palladium.

The third component of the catalyst compositions of the invention is abidentate ligand of phosphorus, nitrogen or sulfur. When a bidentateligand of sulfur is used, the ligand is of the formula

    R--S--R'--S--R                                             (III)

wherein R independently is aliphatic or aromatic of up to 10 carbonsinclusive and R' is a divalent hydrocarbyl linking group of up to 10carbon atoms inclusive with from 2 to 4 carbon atoms inclusive in thebridge. R is suitably hydrocarbyl and groups such as methyl, butyl,hexyl, octyl, phenyl, tolyl or xylyl are useful or R is substitutedhydrocarbyl containing atoms other than carbon and hydrogen, e.g.,2-chloroethyl, 7-bromoheptyl and 4-methoxyphenyl. R' is suitably1,2-ethylene, 1,3-propylene, 1,3-butylene, 2,2-dimethyl-1,3-propylene or2,2,3,3-tetramethyl-1,4-butylene. In the case of bidentate ligands ofsulfur, R is preferably hydrocarbyl and R' is preferably 1,2-ethylene.The sulfur-containing ligands 1,2-di(ethylthio)ethane,1,2-di(benzylthio)ethane and 1,2-di(phenylthio)ethane are preferred.

When a bidentate ligand of nitrogen is employed, the ligand is of thestructure ##STR3## wherein X individually is a divalent linking group ofup to 10 carbon atoms with from 3 to 4 atoms in the bridge, at least twoof which are carbon atoms. Illustrative of suitable bidentate ligands ofnitrogen are 2,2'-bipyridine and 1,10-phenanthroline.

The bidentate ligands of phosphorus which are suitable for the catalystcompositions are represented by the formula ##STR4## wherein R and R'have the previously stated meanings. In the case of suchphosphorus-containing ligands, R is preferably aromatic containing atleast one non-hydrocarbon polar group as a substituent of a ring carbonatom ortho to the ring carbon atom through which the R group isconnected to the phosphorus. The preferred polar substituents are alkoxyand particularly preferred R groups include 2-methoxyphenyl,2-ethoxyphenyl, 2,4-dipropoxyphenyl and 2,4,6-trimethoxyphenyl. Thegroup 2-methoxyphenyl is especially preferred as the R group. Thepreferred R' group for phosphorus bidentate ligands is 1,3-propylene andpreferred bidentate phosphorus ligands are1,3-bis(diphenylphosphino)propane.

In the modifications of the catalyst composition wherein bidentateligands of sulfur or nitrogen are employed, the ligand is provided in aquantity from about 0.5 mol to about 100 mols per mol of palladium, butpreferably in a quantity from about 1 mol to about 50 mols per mol ofpalladium. The use of a bidentate ligand of phosphorus is preferred andsuch phosphorus ligand is used in a quantity from about 0.5 mol to about2 mols per mol of palladium. Quantities of bidentate phosphorus ligandfrom about 0.75 mol to about 1.5 mol per mol of palladium are preferred.

It is useful on occasion to additionally provide to the catalystcomposition an organic oxidizing agent in order to enhance the activityof the catalyst. Illustrative of useful oxidizing agents are aliphaticnitrites, aromatic nitro compounds and hydroquinones, both1,4-hydroquinones and 1,2-hydroquinones. Preferred as the organicoxidizing agent are nitrobenzene and 1,4-hydroquinones such as1,4-benzoquinone and 1,4-naphthoquinone. As stated, the presence oforganic oxidizing agent is not required but amounts up to about 5000mols per mol of palladium are satisfactory. When oxidizing agent ispresent, amounts from about 5 mols to about 5000 mols per mol ofpalladium are preferred.

The catalyst composition is formed by mixing the components thereof. Itis sometimes useful to use a small amount of diluent to facilitate themixing of components. Lower alkanols such as methanol and ethanol aresuitable for this purpose. If diluent is utilized, however, it istypically removed as by evaporation once the catalyst composition isformed. The catalyst composition of the polymerization process of theinvention is employed as a supported or unsupported catalyst. In oneembodiment, the catalyst composition is added directly to the reactor inwhich polymerization is to be conducted as a particulate material or byspraying the catalyst composition into the reactor prior to removal ofdiluent used in the formation of the catalyst composition. In analternate and generally preferred embodiment, the catalyst is formed byimpregnating a solid porous carrier with a solution or slurry ofcatalyst composition followed by removal of any diluent or solvent. Awide variety of catalyst supports are useful including inorganicsupports such as silica, alumina and talc as well as organic supportssuch as charcoal, cellulose and dextrose and polymers such aspolyethylene, polypropylene or polystyrene. A preferred catalystsupport, however, is a previously prepared linear alternating polymer ofthe same general type as that being prepared in the polymerizationprocess. By whatever embodiment, sufficient catalyst is used to providefrom about 1×10⁻⁷ mol to about 1×10⁻³ mol of palladium per mol of totalethylenically unsaturated hydrocarbon. Amounts of catalyst sufficient toprovide from about 1×10⁻⁶ mol to about 1×10⁻⁴ mol of palladium per molof total ethylenically unsaturated hydrocarbon are preferred.

The polymerization is conducted by contacting the carbon monoxide andethylenically unsaturated hydrocarbon reactants in the gas phase in thesubstantial absence of liquid reaction diluent in the presence of thecatalyst composition under polymerization conditions. The molar ratio ofcarbon monoxide to total ethylenically unsaturated hydrocarbon isusefully from about 10:1 to about 1:10 but preferably is from about 5:1to about 1:5. Polymerization conditions typically include a reactiontemperature from about 25° C. to about 150° C., preferably from about30° C. to about 130° C. The polymerization pressure is from about 2 barto about 150 bar, but pressures from about 5 bar to about 100 bar aremore frequently employed. On occasion, it is helpful to provide to thereaction mixture a small amount of hydrogen or lower alkanol, e.g.,methanol or ethanol. The addition of such materials is thought toimprove the activity of the catalyst.

The polymerization process is conducted in a batchwise manner or isconducted continuously or semi-continuously. The polymer product isuseful as recovered or is purified as by contact with a solvent orcomplexing agent selective for catalyst residues. If desired, thepolymer is separated from any catalyst support as by dissolving thepolymer in a selective solvent such as m-cresol orhexafluoroisopropanol. When the preferred linear alternating polymercatalyst support is employed, however, it is generally unnecessary toseparate the polymer product form the structurally similar support.

The polyketone polymers are thermoplastic materials of relatively highmelting point and are useful in the utilities normally associated withconventional thermoplastics but additionally are useful as engineeringthermoplastics. They are processed by methods which are conventional forthermoplastics, e.g., extrusion, injection molding and thermoforming,into a variety of shaped articles of established utility. Specificapplications include containers for food and drink and parts andhousings for automotive applications.

The invention is further illustrated by the following ComparativeExperiments (not of the invention) and the Illustrative Embodimentswhich should not be regarded as limiting. In all cases when substantialpolymer was formed, the polymer was examined by ¹³ C-NMR and found to belinear in structure with units derived from carbon monoxide alternatingwith units derived from ethylene.

ILLUSTRATIVE EMBODIMENT I

A carbon monoxide/ethylene copolymer was produced by absorbing on 8g ofa linear alternating copolymer of carbon monoxide and ethylene acatalyst solution containing 1.5 ml methanol, 0.5 ml tetrahydrofuran,0.0095 mmol palladium acetate, 0.028 mmol boron trifluoride diethylether etherate, and 0.0104 mmol1,3-bis[di(2-methoxyphenyl)phosphino]propane. This supported catalystwas charged to an autoclave of 300 ml capacity equipped with amechanical stirrer. After the air in the autoclave was removed byevacuation, the autoclave and contents were heated to 85° C. and anequimolar mixture of carbon monoxide and ethylene was introduced until apressure of 50 bar was reached and hydrogen was added until a totalpressure of 55 bar was obtained. During the resulting polymerization,the pressure was maintained at 55 bar by the addition of supplementalequimolar mixture. After 10 hours, the polymerization was terminated bycooling the reaction mixture to ambient temperature and releasing thepressure.

The yield of copolymer was 89.4 g, obtained at a rate of 7.9 kg ofcopolymer/g Pd hr.

ILLUSTRATIVE EMBODIMENT II

A copolymer of carbon monoxide and ethylene was obtained by a proceduresubstantially similar to that of Illustrative Embodiment I except thatthe catalyst solution contained 0.024 mmol antimony pentafluorideinstead of the boron trifluoride etherate and the reaction time was 4hours instead of 10 hours.

The yield of copolymer was 32.6 g, obtained at a rate of 6.1 kg ofcopolymer/g Pd hr.

ILLUSTRATIVE EMBODIMENT III

A carbon monoxide/ethylene copolymer was obtained by a proceduresubstantially similar to that of Illustrative Embodiment I except thatthe catalyst solution contained 0.028 mmol aluminum trifluoride insteadof the boron trifluoride etherate and the reaction time was 4.4 hoursinstead of 10 hours.

The yield of copolymer was 20.4 g, obtained at a rate of 2.8 kg ofcopolymer/g Pd hr.

ILLUSTRATIVE EMBODIMENT IV

A carbon monoxide/ethylene copolymer was produced by a proceduresubstantially similar to that of Illustrative Embodiment I except thatthe catalyst solution contained 0.19 mmol of boron trifluoride diethylether etherate instead of 0.028 mmol and the reaction time was 4.2 hoursinstead of 10 hours.

The yield of copolymer was 20.3 g, obtained at a rate of 2.9 kg ofcopolymer/g Pd hr.

COMPARATIVE EXPERIMENT I

A copolymer of carbon monoxide and ethylene was produced by a proceduresubstantially similar to that of Illustrative Embodiment I except thatthe catalyst solution contained 0.028 mmol trifluoromethanesulfonic acidinstead of the boron trifluoride etherate and the reaction time was 5hours instead of 10 hours.

The yield of copolymer was 15.6 g, obtained at a rate of 1.5 kg ofcopolymer/g Pd hr.

COMPARATIVE EXPERIMENT II

A carbon monoxide/ethylene copolymer was produced by a proceduresubstantially similar to that of Illustrative Embodiment I except thatthe catalyst solution contained 0.19 mmol trifluoromethanesulfonic acidinstead of the boron-trifluoride-etherate and the reaction time was 4.8hours instead of 10 hours.

The yield of copolymer was 10.9 g, produced at a rate of 0.6 kg ofcopolymer/g Pd hr.

COMPARATIVE EXPERIMENT III

A carbon monoxide/ethylene copolymer was produced by a proceduresubstantially similar to that of Illustrative Embodiment I except thatthe catalyst solution contained 0.024 mmol p-toluenesulfonic acidinstead of the boron trifluoride etherate and the reaction time was 4.6hours instead of 10 hours.

The yield of copolymer was 16.8 g, obtained at the rate of 1.9 kg ofcopolymer/g Pd hr.

COMPARATIVE EXPERIMENT IV

A copolymer of carbon monoxide and ethylene was obtained by a proceduresubstantially similar to that of Illustrative Embodiment I except thatthe catalyst solution contained 0.19 mmol p-toluenesulfonic acid insteadof the boron trifluoride etherate and the reaction time was 4.6 hoursinstead of 10 hours.

The yield of copolymer was 8.3 g, obtained at a rate of 0.1 kg ofcopolymer/g Pd hr.

What is claimed is:
 1. A catalyst composition useful in the gas-phaseproduction of linear alternating polymers of carbon monoxide and atleast one ethylenically unsaturated hydrocarbon comprising (a) acompound of palladium, (b) a Lewis acid of the formula MF_(n) wherein nis 3 or 5 and M is a Group III or V element which forms a binaryfluoride, said Lewis acid present in an amount of from about 0.5 to 200mols per mol of palladium compound, and (c) a bidentate ligand of:(i)sulfur represented by the formula

    R--S--R.sup.1 --S--R

wherein R independently is aliphatic or aromatic of up to 10 carbonsinclusive and R¹ is a divalent hydrocarbyl linking group of up to 10carbon atoms inclusive with from 2 to 4 carbon atoms inclusive in thebridge, (ii) nitrogen represented by the formula ##STR5## wherein Xindividually is a divalent linking group of up to 10 carbon atoms withfrom 3 to 4 atoms in the bridge, at least two of which are carbon atoms,or (iii) of phosphorus represented by the formula ##STR6## wherein R andR' have the previously stated meanings, said ligand present in an amountfrom about 0.5 to 100 mols per mol of palladium.
 2. The catalystcomposition of claim 1 wherein the compound of palladium is a palladiumcarboxylate.
 3. The catalyst composition of claim 1 wherein n is
 3. 4.The catalyst composition of claim 3 wherein R' is 1,3-propylene.
 5. Thecatalyst composition of claim 1 wherein the bidentate ligand is1,3-bis[di(2-methoxyphenyl)phosphino]propane.
 6. The catalystcomposition of claim 1 wherein R is aromatic with at least one alkoxygroup substituted on a ring carbon atom ortho to the carbon atom throughwhich the R group is connected to the phosphorus.
 7. The catalystcomposition of claim 6 wherein the bidentate ligand is1,3-bis[di(2-methoxyphenyl)phosphino]propane.
 8. The catalystcomposition of claim 7 wherein the Lewis acid is aluminum trifluoride.9. The catalyst composition of claim 7 wherein the Lewis acid is borontrifluoride.
 10. The catalyst composition of claim 9 wherein the borontrifluoride is provided as the diethyl ether etherate.